TORONTO, April 18 /CNW/ - Taking an innovative approach to the
investigation of genetic syndromes causing learning disabilities and mental
retardation, researchers at The Hospital for Sick Children (SickKids) and
Harvard Medical School have found that neural stem cell development during
embryogenesis may have a direct effect on abnormal brain development. This
research is reported in the April 19 issue of Neuron.
Typically studies of this nature focus on problems with how neural
circuits function. These neural circuits form the nervous system and without a
properly functioning circuit, a host of complications and disorders can arise.
Investigating this problem from a different angle, the SickKids team decided
to look at how neural circuits are formed, and more importantly, how nerve
cells develop during embryogenesis.
"We thought that some of these genetic defects might be related to neural
stem cell function, and lead to abnormal development right from the start,"
said Dr. Freda Miller, the study's principal investigator, a senior scientist
in Developmental Biology in the SickKids Research Institute, a professor of
Molecular and Medical Genetics, and Physiology at the University of Toronto
and Canada Research Chair in Developmental Neurobiology. "We identified a
protein that tells stem cells to make neurons during embryogenesis. This
protein is implicated in a human genetic syndrome, and we then showed that the
mutant form of the protein disturbs this stem cell differentiation into nerve
cells, something that has significant bearing on the development of learning
disabilities and mental retardation."
Miller and her team focused on the human genetic disorder Noonan
syndrome, a disorder where the SHP-2 protein is mutated, causing abnormal
development of multiple parts of the body. The team found that mutation of
this protein changed how neural stem cells generate the different cells of the
embryonic brain; when SHP-2 was altered in a mouse model of Noonan syndrome,
early neural development was disturbed.
"This suggests that the human problems likely arise, at least in part
from altered neural stem cell function," adds Miller.
In addition, there is a family of related disorders, including Costello
syndrome and Cardio-facio-cutaneous (CFC) syndrome, which show severe mental
retardation, and which the research team predicts would have similar problems
with neural stem cells. The group is now hoping to ask if similar alterations
might underlie the neural problems in these genetic disorders.
Members of the research team were Dr. David Kaplan, Andrée Gauthier and
Oliva Furstoss from SickKids, and Toshiyuki Araki, Richard Chan and Benjamin
Neel from Harvard Medical School.
This research was funded by the Canadian Institutes of Health Research,
the National Institutes of Health and SickKids Foundation.
The Hospital for Sick Children (SickKids), affiliated with the University
of Toronto, is Canada's most research-intensive hospital and the largest
centre dedicated to improving children's health in the country. As innovators
in child health, SickKids improves the health of children by integrating care,
research and teaching. Our mission is to provide the best in complex and
specialized care by creating scientific and clinical advancements, sharing our
knowledge and expertise and championing the development of an accessible,
comprehensive and sustainable child health system. For more information,
please visit www.sickkids.ca. SickKids is committed to healthier children for
a better world.
For further information:
For further information: Chelsea Novak, Public Affairs, The Hospital for
Sick Children, (416) 813-5045, firstname.lastname@example.org